Download Coagulase-negative Staphylococcus Species Information Sheet

Coagulase Negative Staphylococci
Background
Coagulase-negative Staphylococci (CNS) are normally found on the teat, nasal tissue, and are
found on the hands of milking personnel. The CNS group is made up of over 50 bacteria and are
most frequently isolated from infected glands. This group includes S. chromogenes, S. hyicus, S.
simulans, and S. epidermidis. (S. xylosus, S. saprophyticus, S. sciuri, and S. cohni are the
Novobiocin-resistant Staphylococci and are found free-living in the environment. These bacteria
are considered environmental causes of mastitis). Due to their high prevalence, CNS infections are
usually subclinical, but can result in a 2-3 times increase in SCC in infected quarters. The amount
of increase in SCC is reflective of the Staphylococcus species causing the infection.
Source and Transmission
CNS are found in the environment and are opportunistic bacteria that can cause infection when
teats and equipment are not properly disinfected. First lactation cows are at a higher risk of
infection than older cows.
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Attainment: < 1,000 CFU/mL in BTM
Disease
Low levels of CNS bacteria can represent normal flora, whereas high levels indicate poor udder
preparation and teat sanitation, or environmental contamination of equipment. Most CNS infections
are subclinical and the clinical cases are normally mild and transient. SCCs will elevate to no more
than 500,000 cells/ml and rarely impact milk production. However, there are some species of CNS
that can be more pathogenic and can cause a decrease in milk production. Since CNS are part of
the normal teat flora, isolating these organisms does not necessarily mean that there is a mastitis
infection, so clinical symptoms and SCCs should be considered when interpreting CNS positive
cultures.
Treatment
Subclinical infections of CNS do not have to be treated because they are usually mild and do not
have many economic ramifications for dairy producers. Often the affected cow will spontaneously
cure herself and the infection will be resolved without treatment. It is recommended to treat clinical
cases, especially if the infection is persistent. CNS are sensitive to most antibiotics and treatment
duration for CNS is generally short.
CL-RES-64
In Use: 1/4/2016
Prevention and Control
To prevent CNS mastitis proper pre- and post-milking teat disinfectant protocols should be used.
Contamination can be reduced by milking clean, dry teats. Dry cow therapy can also be an
effective control method and can eliminate about 90% of CNS infections.
References
Managing Mastitis, the Pathogen Series. Coagulase Negative Staphylococci
http://milkquality.wisc.edu/wp-content/uploads/2013/05/coagulase-negative-staph-fact-sheet.pdf .
Accessed 6/25/15
Coagulase Negative Staphylococci (CNS) Mastitis Pathogen Factsheet #5 Accessed
http://www.vdl.umn.edu/prod/groups/cvm/@pub/@cvm/@vdl/documents/content/cvm_content_474
083.pdf. Accessed 6/25/15
Coagulase-negative Staphylococci Infections
http://www.nmconline.org/coagneg.htm . Accessed 6/25/15
Laboratory Handbook on Bovine Mastitis. National Mastitis Council, Inc. Revised 1999.
CL-RES-64
In Use: 1/4/2016